Pin badges for me.
I can imagine the likes of a yearly frightfest one but also film specific ones?
The swapping and sought after-ness could rival the football panini sticker days.
The foyer at the venue may sound a bit like this:

" ill swap you my nappy pin of "Attack of the adult babies" for your chainsaw pin of "Leatherface"?

or

" Have you got the Pin from the 2020 frightfest? you know, the one when Ian puked on that guy in the front row when his phone went off"

And they can attach the pins to the Lanyards or festival bags.

I`m just thinking out loud here

"He`ll forgive them.He will forgive them and allow them into heaven, I cant live with that"
Twitter: zombieslew